/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.activiti.engine.delegate.event;

import org.activiti.engine.EngineServices;

/**
 * Describes an event that occurred in the Activiti Engine which is dispatched to external
 * listeners, if any.
 *
 * @author Frederik Heremans
 */
public interface ActivitiEvent {

    /**
     * @return type of event.
     */
    ActivitiEventType getType();

    /**
     * @return the id of the execution this event is associated with. Returns null, if the event
     * was not dispatched from within an active execution.
     */
    String getExecutionId();

    /**
     * @return the id of the process instance this event is associated with. Returns null, if the event
     * was not dispatched from within an active execution.
     */
    String getProcessInstanceId();

    /**
     * @return the id of the process definition this event is associated with. Returns null, if the event
     * was not dispatched from within an active execution.
     */
    String getProcessDefinitionId();

    /**
     * @return the {@link EngineServices} associated to the engine this event
     * originated from. Returns null, when not called from within a listener call or when no
     * Activiti context is active.
     */
    EngineServices getEngineServices();
}
